205 citations · 1.4k across the 44 of their papers we have counts for
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A quantitative NLTE analysis of visual and ultraviolet spectra of four helium-rich subdwarf O stars
Markus Schindewolf, Peter Nemeth, Ulrich Heber +4
Hot subdwarfs represent a poorly understood late phase of stellar evolution. While binary evolution plays an important role for B-subdwarfs (sdB), the origin of the He dominated O-…
Hypervelocity stars in the Gaia era: Runaway B stars beyond the velocity limit of classical ejection mechanisms
Andreas Irrgang, Simon Kreuzer, Ulrich Heber
Young massive stars in the halo are assumed to be runaway stars from the Galactic disk. Possible ejection scenarios are binary supernova ejections (BSE) or dynamical ejections from…
A quantitative spectral analysis of 14 hypervelocity stars from the MMT survey
Andreas Irrgang, Simon Kreuzer, Ulrich Heber +1
Hypervelocity stars (HVSs) travel so fast that they may leave the Galaxy. The tidal disruption of a binary system by the supermassive black hole in the Galactic center is widely as…
NLTE spectroscopic analysis of the He anomaly in subluminous B-type stars
D. Schneider, A. Irrgang, U. Heber +2
Several B-type main-sequence stars show chemical peculiarities. A particularly striking class are the He stars, which exhibit a remarkable enrichment of He with respect to…